Sewing machine



I SPf- 17,1935,

I F; L-UTz SEWING MACHINE l l Aug.A 2l,

2 Sheets-sheet 1' F. LUTZ SEWING MACHINE Sept. 17, v1935.

Filed Aug. 2L, 1933 2 Sheets-Sheet 2 Patented sept. 11,1935

UNITED STATES SEWING MACHINE Friedrich Lutz, Stuttgart, Germany, assigner to Union Special Maschinenfabrik, G. m. lb. H.,

iStuttgart, Germany Application August 21, 1933, Serial No. 686,151

- In Germany December 9, 1932 claims. (ci. 11a-154) Figure l is a view from the rear of the machine showing the sewing machine moreor less diagrammatically with the improvements added f thereto; A N Fig. 2 is a vertical sectional view substantially on the line of feed and showing a portion only of the sewing machine;

Fig. 3 is a plan view showing a portion of th machine in broken lines, a portion of the machine in horizontal section, and the improvements in top plan, and

Fig. 4 is a view partly in plan and partly in section from the front of the machine, the section being taken through the presserl foot directly in rear of the needle.

AConsiderable diiilculty has been experienced in l producing a strong seam of neat appearance, especially in sewing paper material, such as paper bags, with a cross thread such as jute or sisal, which thread has little or no elasticity. The

thread often cuts the paper between the needle Y punctures therein, particularly when the needleV thread is placed under suillcient tension to make a relatively tight stitch. 'I'he present invention has to do with an attachment to a chain stitch sewing machine which includes a nger that is placed in rearof the needle so that the needle on its down stroke will lay4 the thread between the previous stitch puncture and the stitch puncture about to be4 made over the finger, andthe nger Isupports the thread during the concatenating of the thread loops, after which the finger is withdrawn so that on the up stroke of the needle, the

, thread loops will be drawn into a substantially fili tight concatenation. This relieves all cutting strain of the thread on the material between the needle punctures and permits a relatively tight stitch'to b e made. Furthermore, when there is no material being stitched, the finger will support 60 the thread and aid in chaining between stitched articles.

Referring more in detail to the drawings, the sewing machine which is illustrated more or less diagrammatically, includes a standard I, and an 65 -ovcrhanging armv 2 carried thereby in which the the recess and the bottom of the foot.

. of the presser foot II.

'needle bar 3 reciprocates. Said needle bar carries a needle 4. The needle ba-r'is reciprocated by means of a needle lever 5. Beneath the overhanging arm is a work supporting arm 6 in which is located a feeding mechanism including a feed dog 'I which is of the usual construction. Cooperating with the needle beneath the work support is a thread carrying looper 8 mounted on a carrier 9 which is pivoted for oscillation on a looper support Ill. The looper is given the usual move- 10 ments into and out of the needle loops and a needle avoiding movement. I

The material is held on the work support by a presser foot il. Said presser footvhas an upturned toe l2 and an opening I3 through whichdd the needlepasses. Directly in rear of the needle opening I3, the presser foot is provided with a recess Ill which 'extends down into the presser foot, leaving only a thin portion of metal between f Mounted 2* for oscillation in a plane at right angles to the feed is a finger I5 carried by a shank portion IB which is adjustably attached to an arm il. The arm I1 is carried by a yoke member I8. This yoke member is provided with sleeves IB and 2li. 25 The sleeve I9 is 'journaled' on a bearing carried i by a `bolt 2i which extends through the shank 22 Mounted on the presser foot is an upstanding frame member 23 and the sleeve 20 is journaled on a pin carried by this 30 'member 23. 'I'hus it is that the finger can oscillate about a pivotal axis which is directly over thel1-ne` of feed and intersects the path of reciprocation of the needle.v

The finger I5 is timed in its movements so 35 that it moves across the line of feed when the needle is in the upper portion of its down stroke,

and the finger will, therefore, pass between the needle thread running from the eye of'the needle to the previous stitch and the path of recipro- 40 cation of the needie, so that as the needle continues to descend, it will lay the thread over the nger, and the finger will support the thread as the needle passes on down to. the lower .end of its stroke. l This takes all strain oil the material between the needle punctures. On the up stroke of the needle, the finger is oscillated so that it A withdrawn from beneath the thread, releasing the same, so that as. the feed of the fabric takes place, and the needle passes on to the upper end of its stroke, the thread loops which have been concatenated will be drawn down tight, setting the@ stitch. Inasmuch as the nger oscillates about av pivot axis which is'directly over the line olf feed said nger moves in adlrect-ibn substantially parallel with the surface of the fabric. It is relatively smooth and small, and while it serves as a support for the thread during the down stroke of the needle and over which the thread is drawn it may be readily withdrawn to permit the drawing down and the setting of the stitch as noted above.

'I'he yoke I8 carrying this finger I5 is provided with an upstanding arm 2l. A link 25 is pivoted at 26 to said arm, and is also pivoted at 21 to an arm 28 which is attached to the shaft 25, and this shaft 29. is fixed to the needle lever lforming a support for the needle lever and isI oscillated by the needle lever. When the needle lever 5 is turned in a clockwise direction as view`ed` in.Fig. 1, the finger I5 will be projected across the line of feed and between the needle thread and the needle, as described above. This is on the downward movement of the needle, and when the needle is retracted, then the lever 5 will turn in a counter-clockwise direction, and pushing on the link 25 will swing the yoke so as to retract the finger'.

From the above it will be apparent that a means has been provided which supports the thread between the needle punctures while the needle is movingto the lower end of its stroke so asto take all strain oif the material being stitched. If there is no material being stitched, the thread will be supported and insure a concatenation of the thread loops and the forming of enchained stitches between stitched articles. The finger moves very close to the upper face of the material being stitched, due to the fact that the presser foot is recessed so as to provide a clearance space inv which the fingertswings. While the thread is supported, it is not unduly extended, so that the needle and the usual threadd controlling devices cooperating therewith can take up the slack created in the thread by the supporting finger 'and draw the stitches tight when the iingerreleases the thread.

It is obvious that minor changes in the details of construction and the arrangement of the parts may be made without departing from the spirit of the invention as set forth in the appended claims.

Having thus described the invention, what I claim as new and desire to secure by letters- Patent, is-

1. The combination of a needle, a complemental stitch forming device cooperating therewith for forming stitches, means located in rear of the needle over which the n'eedle thread between stitches 'is laid, so that the thread is supported thereby on` the down stroke of the needle, and means for moving s aid thread supporting means in a direction substantially parallel with the surface of the fabric for releasingthe thread whereby the needle on its up stroke may set the stitch and draw `the threads into firm contact with the fabric being stitched.

2. The combination of a needle, a thread carrying looper cooperating therewith for forming 5 stitches, a thread finger located in rear of the needle over which the needle thread between stitches is laid so that the thread is supported thereby on the down stroke of the needle. and, means for moving said finger in a direction substantially parallel with the surface ofthe fabric and from beneath the thread for releasing the same so that the needle on its up stroke will set the stitch and drawV the threads into firm engagement with the fabric being stitched 3. 'I'he combination of a needle, a thread carrying looper cooperating therewith for' forming stitches, a smooth thread nger located in rear of the needle, means for supporting said thread finger whereby said finger moves on substantially a line parallel with the surface of the fabric, meansfor oscillating said thread finger in timing with the reciprocation of the needle so that said thread finger is passed between the needle thread and the path of the needle while the needle is on its down stroke whereby said needle as it mov to the lower end of its stroke draws said needle thread between needle punctures over said finger. said finger being retracted from beneath the thread on the up stroke of the needle so as to permit the stitches to be set and the threads drawn into firm contact with'the fabric being stitched.

4. The combination of a work support, a presser foot, a needle, a thread carrying looper cooperating withsaid needle, a. needle thread support- 36 ing finger located above the presser foot and in rear 'of the needle, and means for oscillating said thread finger in a direction substantially parallel with the surface of the fabric whereby said nger is moved between the needle thread and 40 the needle oh the down stroke of the'needle for supporting said thread and is retracted on the up stroke of the needle for permitting the setting of the stitches.

5. 'I'he combination o'f a work support, a presser 45 footl having a needle opening therethrough and a recess in its upper face in rear of said opening, a needle, a thread carrying looper cooperating with said needle, a thread supporting finger mounted for oscillation in substantially a vertical plane in rear of the needle and in said recess, means for oscillating said finger in a direction substantially parallel with the surface of the fabric whereby said finger is passed between the needle thread and the needle on the down stroke of the needle for supporting the thread between needle punctures and is retracted to permit the needle on its up stroke to set the stitches.

" FRIEDRICH LUIZ. 

